The background description provided here is for the purpose of generally presenting the context of the disclosure. Work of the presently named inventors, to the extent it is described in this background section, as well as aspects of the description that may not otherwise qualify as prior art at the time of filing, are neither expressly nor impliedly admitted as prior art against the present disclosure.
Substrates such as semiconductor wafers are produced by depositing, etching and patterning film layers. Deposition processes include physical vapor deposition (PVD), chemical vapor deposition (CVD) and atomic layer deposition (ALD). In some circumstances, a seed layer is deposited at bottoms of features such as trenches or vias. However, none of these deposition processes is able to selectively deposit material on bottom surfaces of trenches or vias. These deposition processes can only perform conformal or non-selective seed deposition. Other disadvantages of these deposition processes include pinch-off at openings of the features and seams/roughness resulting from sidewall growth.